Aviation Materials Research Articles

Enhancing aviation safety: Multifunctional graphene nanostructured foams for lightweight fire suppression materials

Fuel tank fires and explosions are the primary causes of military and civilian aircraft losses and have been a major concern for the aviation and defense industries. Passive protection systems with explosion-suppression materials generate a protected environment within fuel tanks before ignition can occur and help prevent catastrophic failures. To minimize these concerns, open-cell reticulated polyurethane foams are extensively used in passive protection systems. However, fire- and explosion-related incidents are still taking place and need to be urgently addressed for aviation safety. This study investigates the effects of graphene nanostructured foams for redesigning the next-generation lightweight fire-retardant materials in aviation. Graphene foams have a unique open-cell morphology with three dimensional (3D) continuous and interconnected network structures and hollow features, which can be suitable for aircraft and defense applications. In this study, mechanical and thermal characterizations tests were conducted on graphene nanostructured foams for a better evaluation. Mechanical loading-unloading studies highlighted their outstanding mechanical energy-absorption capabilities against external loads. The thermogravimetric analysis revealed that the graphene foams provided excellent thermal properties against fire and high-temperature degradation. It was also confirmed that graphene foams uniquely manifested self-extinguishing characteristics during burning tests without catching fire or dripping for secondary fire formations. According to the tube explosion experiments, the graphene foams kept their appearance and strength after blast impacts and elevated explosion temperatures and shock waves. As a result, the proposed multifunctional graphene micro- and nanofoams offer significant potential for the next-generation fire- and explosion-suppression materials in various critical industries, such as aircraft, defense, space, drone, energy, and automotive.

Mechanistic Model of Fatigue in Ultrasonic Assisted Machining.

Anti-fatigue design in the machining process of aviation material requires advanced processes to enhance the surface integrity and a holistic model which can optimize the process aiming at maximum fatigue life. In the present study, the axial ultrasonic assisted milling process was utilized to machine the Inconel 718 while the process executes the thermomechanical cutting and peening action simultaneously. To optimize the process factors, a hybrid model using a combination of regression analysis and an analytical model was developed to correlate the machining factors, i.e., vibration amplitude, cutting velocity and feed rate to fatigue life. Herein, the former was used to map the process inputs to surface integrity aspects (SIAs), viz. roughness, hardness and residual stress; then, the SIA was mapped to fatigue life through a stress-based approach. The obtained results revealed that there is close agreement between the measured and predicted values of fatigue life where the prediction error is less than two times the dispersion. On the other hand, applying ultrasonic vibration at the highest amplitude together with the maximum feed rate and cutting velocity yield significant improvement in fatigue life, i.e., three times the same condition without ultrasonic vibration in light of the enhancement of compressive residual stress and work hardening of the surface layers.

Analysis of the possibility of using smart materials in aviation

The article presents the basic types of intelligent materials and their properties. Examples of applications of this type of materials in the aviation industry were mentioned and an attempt was made to analyze the possibilities of their use in the future. Possible development directions for the use of intelligent materials in aviation were determined.

ИССЛЕДОВАНИЕ ДИНАМИЧЕСКИХ СВОЙСТВ ГИБРИДНОГО ТИТАН-ПОЛИМЕРНОГО КОМПОЗИЦИОННОГО МАТЕРИАЛА

Low specific weight and high mechanical strength (especially at elevated temperatures) of titanium and its alloys make them very valuable aviation materials. In the field of aircraft construction and aircraft engine production, titanium is increasingly replacing aluminum and stainless steel. At present, aircraft developers are restructuring the whole material science concept of aircraft construction, actively involving and using various types of composite materials based on titanium alloys. Combined with the properties of titanium, FML composites based on titanium have greater stiffness, impact resistance, heat resistance, and corrosion resistance especially compared to similar aluminum-based materials. The paper investigates the dynamic characteristics of hybrid titanium-polymer composite materials (TPCM) based on titanium alloy BT-23 and fiberglass with a brief presentation of the main characteristics of prepregs. The process of manufacturing specimens for testing including heat treatment, ply laying scheme and reinforcement scheme in two variants is described. The results of experimental studies of natural frequencies and damping coefficient by the method of free damped oscillations in free oscillations of TPCM plates are presented. The tests are carried out on a specially designed unit with a triangulation sensor in the variant of vertical loading. Two identical specimens with different overall dimensions are tested.Each specimen was tested with a different amplitude. Five tests were conducted for each amplitude. The physical constants of the specimens were pre-determined in static tests. The natural frequencies and damping coefficients for the titanium-polymer composite specimens were found.

Ultrasonic vibration cutting of advanced aerospace materials: a critical review of in-service functional performance

PurposeUnconventional machining processes, particularly ultrasonic vibration cutting (UVC), can overcome such technical bottlenecks. However, the precise mechanism through which UVC affects the in-service functional performance of advanced aerospace materials remains obscure. This limits their industrial application and requires a deeper understanding.Design/methodology/approachThe surface integrity and in-service functional performance of advanced aerospace materials are important guarantees for safety and stability in the aerospace industry. For advanced aerospace materials, which are difficult-to-machine, conventional machining processes cannot meet the requirements of high in-service functional performance owing to rapid tool wear, low processing efficiency and high cutting forces and temperatures in the cutting area during machining.FindingsTo address this literature gap, this study is focused on the quantitative evaluation of the in-service functional performance (fatigue performance, wear resistance and corrosion resistance) of advanced aerospace materials. First, the characteristics and usage background of advanced aerospace materials are elaborated in detail. Second, the improved effect of UVC on in-service functional performance is summarized. We have also explored the unique advantages of UVC during the processing of advanced aerospace materials. Finally, in response to some of the limitations of UVC, future development directions are proposed, including improvements in ultrasound systems, upgrades in ultrasound processing objects and theoretical breakthroughs in in-service functional performance.Originality/valueThis study provides insights into the optimization of machining processes to improve the in-service functional performance of advanced aviation materials, particularly the use of UVC and its unique process advantages.

Fabricating advanced MXene-based hybrid materials to elevate fire safety and mechanical strength in carbon fiber-reinforced bismaleimide resins

Bismaleimide (BMI) resin holds great significance to the aerospace field, however, the limited toughness and inadequate fire resistance impede its broader application area. The addition of carbon fiber (CF) can enhance the toughness of BMI resin, but fire safety and interfacial stability between CF and BMI matrix need to be further considered. Here, the carbon fiber-reinforced BMI resin laminate was designed to improve fire resistance, mechanical properties, and interfacial affinity based on a novel P, N, and Si surface-modified flame retardant (MX@HBET) and silane-modified CF. Upon addition of 1 wt% MX@HBET to BMI/CF composites, the total heat release and total smoke production respectively exhibited 10.73 % and 33.3 % reduction. Furthermore, the laminate exhibited significant fire resistance when exposed to butane flame (1500 °C) and the backplane temperature was maintained at approximately 430 °C for 20 min. In addition, the impact and tensile strengths of the laminate respectively reached 82.10 kJ/m2 and 466.6 MPa (pure BMI/CF corresponding to 63.52 kJ/m2 and 350.1 MPa). In brief, the flame resistance and mechanical performance enhanced greatly via the introduction of modified MXene and CF, providing promising prospects for the application of aviation materials in extreme conditions.

Research Progress and the Prospect of Damping Magnesium Alloys.

As the lightest structural metal material, magnesium alloys possess good casting properties, high electrical and thermal conductivity, high electromagnetic shielding, and excellent damping properties. With the increasing demand for lightweight, high-strength, and high-damping structural materials in aviation, automobiles, rail transit, and other industries with serious vibration and noise, damping magnesium alloy materials are becoming one of the important development directions of magnesium alloys. A comprehensive review of the progress in this field is conducive to the development of damping magnesium alloys. This review not only looks back on the traditional damping magnesium alloys represented by Mg-Zr alloys, Mg-Cu-Mn alloys, etc. but also introduces the new damping magnesium materials, such as magnesium matrix composites and porous magnesium. But up to now, there have still been some problems in the research of damping magnesium materials. The effect of spiral dislocation on damping is still unknown and needs to be studied; the contradiction between damping performance and mechanical properties still lacks a good balance method. In the future, the introduction of more diversified damping regulating methods, such as adding other elements and reinforcements, optimizing the manufacturing method of damping magnesium alloy, etc., to solve these issues, will be the development trend of damping magnesium materials.

Development of a Cognitive Assessment Instrument for Simple Business, Energy and Aircraft Materials via Wordwall

Cognitive assessment of kids who still frequently use paper documents and certain school-provided software. The objective of this study is to develop a legitimate, dependable, efficient, and useful tool that may be used to teach static electricity concepts through wordwalls. This study use the ADDIE model in conjunction with the Research and Development technique. Purposive sampling is the sampling technique used, taking into account samples that have finished business, energy, and basic aviation material for science education. 52 individuals served as the samples. The study is being conducted at SMP 1 PGRI in Semarang City. Using SPSS software version 2019 and Ministep, the data analysis technique involves testing the validity, reliability, efficacy, and practicality of test instruments and questionnaires. The study's findings demonstrate that the creation of a wordwall-based cognitive instrument on static electricity learning outcomes is valid, dependable, and practically implemented, as evidenced by the instrument's 0.79 sufficient category score, 74.9 average score, and 61.40% production rate based on student responses. This means that future researchers can build on this tool to suit their needs and the reference tools that are used to assess learning.

Self‐healing polymers for aviation applications and their impact on circular economy

AbstractPolymers have swiftly replaced conventional metallic materials in aviation due to their lightweight and easy processability. Usages of polymers are presently mostly limited to non‐critical components. Flight safety is paramount in aviation and overrides all other factors. The aviation industry is averse to the usage of polymeric materials in critical component applications owing to the nature of failure being catastrophic. The review has covered various polymeric component failures and their root cause reasons. To overcome the inherent weakness in polymers currently used, a strategy to mimic nature is being explored by researchers. Self‐healing polymers can overtake metals if coupled with safe fail technology. Such materials have additional advantages in terms of enhanced longevity and ultimate life cycle. This review critically analyzed various factors driving research and development of self‐healing material for aviation applications. Various extrinsic and intrinsic self‐healing materials have been reviewed in the present work. Composites with an extrinsic self‐healing mechanism possess good healability and strength and can potentially replace current materials. Further, candidate polymeric materials with intrinsic self‐healing capability for the aviation field are extensively reviewed. Various aviation‐grade polymers like epoxy, Poly(methyl methacrylate), polycarbonate, and elastomeric materials with possible chemistries of intrinsic healing like Diel‐Alder reaction, Shape memory assisted self‐healing and covalently adaptable networks have been critically examined. Authors believe that extrinsic self‐healing technology is mature enough for use in the secondary structure of aircraft. At the same time, present technologies of intrinsic materials are not mature enough for flight safety reasons in aircraft; however, they are candidate materials for UAVs. Fast‐growing aviation field, coupled with the entry of UAVs, calls for environmentally sustainable material support. Therefore, this review explores materials within the sphere of high mechanical properties coupled with a low environmental impact.

Exploration and Practice of Ideological and Political Education in Vocational Education Curriculum Based on Learning as the Center

Anti mold technology in aviation material storage is an important foundational course for aviation material management majors. In order to effectively play the role of the main channel for classroom education, curriculum ideological and political reform has been carried out in the course of curriculum teaching, effectively integrating curriculum ideological and political concepts into professional classrooms. Based on learning as the center, curriculum ideological and political goals have been established, curriculum ideological and political elements have been explored, and the entire process of education mode has been explored. Implementation precautions have been proposed, and ideological and political education has been implicitly embedded in various stages of the teaching process. Through students’ independent participation and self-awareness, ideological and political internalization has been achieved, providing reference and inspiration for the ideological and political reform of other courses.

АВИАСТРОЕНИЕ И РАДИОЛОКАЦИЯ В РАБОТЕ СОВЕТСКИХ НАУЧНО-ИССЛЕДОВАТЕЛЬСКИХ ИНСТИТУТОВ В КОНЦЕ 1930-Х – 1940-Е ГГ.: ИЗУЧЕНИЕ И ИСПОЛЬЗОВАНИЕ ЗАПАДНОГО ОПЫТА. ЧАСТЬ 1

The formation and development of Soviet research institutes in the field of aircraft construction and radar are quite widely represented in historiography. The topic of the transfer of Western technologies to the industry of the USSR in the 1920-1930s is also not new.However, a study of the scientific literature revealed a lack of special studies devoted to the period of the late 1930-1940s. The article, based on unpublished archival documents, is devoted to the analysis of the work of four research organizations involved in developments in the field of aviation industry and radar: Central Aerohydrodynamic Institute (TsAGI), All-Russian Institute of Aviation Materials (VIAM), Research Institute-20 (NII-20), Central Research Institute-108 (TsNII-108). All of them were involved in the study of Western technologies, in which the Soviet Union lagged behind the USA, Great Britain, and Germany.

Design of a 2.7 GPa ultra-high-strength high Co–Ni secondary hardening steel by two-step nano-size precipitation tailoring

High Co–Ni secondary hardening steels are valuable in the field of aviation materials. With the increasing demand of lightweight, further enhancing its strength has received widespread attention. In this study, instead of using only M2C carbides as the reinforcements in the traditional high Co–Ni secondary hardening steels, nano-size NiAl phases were introduced to provide additional strength. To obtain the collaborative precipitation of these two reinforcements, systematically thermodynamic calculation, including the driving force, coarsening rate, etc., was made to quantitatively tailor the composition and the two-step aging parameters. The calculation results showed that adding 1 % Al into the standard composition of M54 is a plan with high potential and a second aging process at 450 °C should be added to promote NiAl precipitation. Based on the experimental validation, the target microstructure formed as the design. With the dual-phase strengthening of NiAl particles and M2C carbides, the yield and tensile strength are greater than 2.3 and 2.7 GPa, respectively, which increases the strength of M54 steel by >30 %, retaining sufficient elongation and relatively low cost. This new designed alloy increased the strength–ductility balance of high Co–Ni secondary hardening steels and aviation maraging steels from ∼12.5 to 13.5 GPa%.

Enhanced Heat Transfer Analysis on MHD Hybrid Nanofluid Flow Over a Porous Stretching Surface: An Application to Aerospace Features

The advancement of aircraft technology has presented manufacturers with new criteria and problems for the functioning of their devices. It is essential that, in order to guarantee the secure operation of aerospace machinery, the failure mechanisms be identified and the operational durability of critical structural components be improved as quickly as possible. New aviation materials have been developed in modern years. In an aviation engine, engine oil lubricates, cools, washes, maintains against rust, decreases sound, and accelerates. Most important is lubrication. All mechanical components would burn out if not maintained. The aim of this work is to minimize costs by extending the operational life of aircraft components (mechanical and motor parts) and enhancing fuel mileage and flying distance. Based on the importance of the inspiration on magnetohydrodynamic Aluminum Oxide-Cobalt hybrid nanofluid flow over a stretching surface (SS) in the existence of porous medium, and thermal radiation are investigated. In this model we used Engine oil mixed with Aluminum Oxide and Cobalt nanoparticles. By using the suitable self-similarity variables, the PDE is transformed into ODEs. After then, the dimensionless equations are solved by using the Maple built in BVP Midrich scheme. Graphs and tables explain how the operational factors affect fluid flow efficiency. Compared to nanofluids, hybrid nanofluids have a better heat transfer rate.

Application of carbon nanotube composite materials in aviation

Carbon nanotube has unique structure, excellent performance, unique one-dimensional hollow structure, and extremely low density. These advantages determine that carbon nanotube has mechanical properties, electrical properties, and adsorption properties that other materials cannot match. Carbon nanotube, as one of the popular research projects of scientists in the world today, has very broad and attractive application prospects in the fields of semiconductor devices, hydrogen storage, sensors, adsorption materials, battery electrodes, catalyst carriers, etc. The field of science and technology also shows great application prospects. Combined with the urgent needs of aircraft in light and high-strength structures, lightweight cables and efficient thermal control, the carbon nanotube is considered to be the booster of the next generation of aerospace and is expected to become an important pillar in the future of aviation. This paper comprehensively analyzes the application of carbon nanotubes in aircraft wheels, aircraft engine blades, aircraft avionics systems and electromechanical system displays and looks forward to its application prospects and feasibility in the aviation field. Developments in aviation present challenges and opportunities.

Aeroelasticity Model for Highly Flexible Aircraft Based on the Vortex Lattice Method

With the increasing use of composite materials in aviation, structural aircraft design often becomes limited by stiffness, rather than strength. As a consequence, aeroelastic analysis becomes more important to optimize both aircraft structures and control algorithms. A low computational cost aeroelasticity model based on VLM and rigid-body dynamics is proposed in this work. UAV flight testing is performed to evaluate the accuracy of the proposed model. Two flight sections are chosen to be modeled based on recorded aerodynamic surface control data. The calculated accelerations are compared with recorded flight data. It is found that the proposed model adequately captures the general flight profile, with acceleration peak errors between −6.2% and +8.4%. The average relative error during the entire flight section is 39% to 44%, mainly caused by rebounds during the beginning and end of pull-up maneuvers. The model could provide useful results for the initial phases of aircraft control law design when comparing different control algorithms.

PDMS-PI composite coating toward multi-purpose development: Hydrophobic, low-friction/wear, and heat-resistance

Despite polyimide (PI) has been regarded as heat-resistant aviation material, but its high friction coefficient and insufficient abrasion resistance hinder the wide application. Herein, a versatile PDMS-PI composite coating with double-layer structure was prepared by crosslinking hybrid. The effect of polydimethylsiloxane (PDMS) on the hydrophobic, heat-resistant and tribological properties of PDMS-PI composite coating was explored. As expected, compared with the PI and SiO2-PI, PDMS-PI coating achieved the contact angle of 108.5° and only 5 wt% heat loss temperature at 578 ℃. Additionally, its wear rate obviously decreased by 38.5 %, and the friction coefficient declined from 0.33 to 0.07. The improvement contributes to excellent hydrophobic and heat resistance of dense protective layer and low-friction/wear of the PDMS coating layer.

On selection of advanced compositions of flame resistant magnesium alloys

Magnesium alloys are among the most advanced structural materials in aviation and mechanical engineering industry due to their low density and high strength-weight ratio, but their ability to ignite at temperatures from 500°C, while actively sustaining combustion, can cause disastrous consequences even in the event of minor emergencies. This paper is intended to investigate the compositions that can enhance flame resistance of magnesium alloys. Comparison was made between ignition temperatures of commercial cast alloy ML10, LPSO-structure alloy, advanced cast alloy with rare earth metals, and variations of these alloys with different additives — agents that improve flame resistance. It has been established that the maximum flame resistance is provided by those alloys that contain both the LPSO phase and the Yb or Ca additive as agents capable of raising the ignition temperature to 1000°C or even higher.

Multifunctional SiC aerogel reinforced with nanofibers and nanowires for high-efficiency electromagnetic wave absorption

Ceramic aerogels with recoverable compressibility, super-insulation capacity, and remarkable thermal and chemical stability are fascinating for use in the field of high-level electromagnetic wave (EMW) absorption. However, integrating multiple functions into a monolithic ceramic aerogel using presently available fabrication techniques remains a challenge. Therefore, we employed a novel strategy to successfully synthesize a multifunctional and monolithic SiC ceramic aerogel using a simple freeze casting technique with a subsequent carbonation and calcination process. The as-synthesized SiC aerogel-2 exhibits ultralow density, fire resistance, high-temperature chemical and thermal stability, and excellent insulating properties. Notably, the one-dimensional SiC nanofibers and nanowires inside the SiC aerogel-2 act as a reinforcement to ensure the presence of a stable porous structure. The sample exhibits excellent mechanical performance and also achieves ideal impedance matching to present high-efficiency EMW-absorbing properties, including a minimum reflection loss (RLmin) of − 61.56 dB and a maximum effective absorption bandwidth (EABmax) of 9.82 GHz. Thus, the successful fabrication of multifunctional SiC aerogels will pave the way for the development and widespread application of high-level EMW absorption materials in aviation and aerospace fields.

Calculating the Surface Layer Thickness and Surface Energy of Aircraft Materials

The surface layer determines the physical properties of aviation materials and, based on these properties, the calculation of surface energy anisotropy can be implemented. Moreover, the value of the surface energy determines the service time and the destruction of aircraft structures surface layer, while the surface layer thickness determines the distance at which this process usually takes place. In this work, a new atomically smooth crystal empirical model is built without considering the surface roughness. This model can be used to theoretically predict the surface energy anisotropy and surface layer thickness of metals and other compounds, in particular the aviation materials. The work shows that the surface layer of an atomically smooth metal, like other compounds, consists of two nanostructured layers: d(I) and d(II). Having sufficient accuracy, the proposed model would allow the prediction of aviation materials performance properties without the need for ultrahigh vacuum or other complicated theoretical methods to analyze the surfaces of nanosystem atomic structures.

Numerical and experimental investigations on the laser assisted machining of the TC6 titanium alloy

In order to improve the machinability of difficult-to-machine materials in aviation, laser-assisted cutting technology has received extensive attention. This method of machining allows the workpiece to obtain a localized high temperature prior to cutting in order to benefit from thermal softening. A 3D transient laser heating model was developed for the finite element method to predict the preheating temperature of the cutting layer. The effect of cutting parameters (cutting speed, feed rates, depth of cut) on the magnitude, frequency and amplitude of the cyclic cutting forces was investigated both in conventional machining and in laser assisted machining. It is founded that the laser assistance decreases the flow stress of the material, magnitude of cutting forces and the amplitude of cutting forces. But the frequency of circulating cutting forces increase comparing with the CM (conventional machining). In addition, this paper considers the effect of the LAM (laser-assisted machining) technique on reducing the magnitude of cutting force fluctuations, which results in a flatter machined surface profile and reduces the number of surface defects. A chip morphology different from that of CM is created due to the influence of the cutting force by the temperature field in LAM. Furthermore, a “transitional chip” is discovered, which is a transition from a continuous chip to a segmented chip. The completely thermal-mechanical coupled orthogonal cutting model was established to reveal the evolution mechanism of shear band formation with laser assistance. The results show that shear bands can be formed faster and with less stress in LAM compared to CM. The model can effectively predict the shear angle and keep the prediction error within 10 %. The shear band formation processes in both machining methods were uncovered according to the models. The developed model is very useful for understanding the chip formation process and the cutting force variation in laser assisted machining.